Install rbenv and Ruby:
$ brew install rbenv
$ rbenv install 2.5.1 # latest stable as of 2018-08-12
$ rbenv global 2.5.1
Install Jekyll and Bundler:
$ gem install jekyll bundler
In the blog directory, run:
$ bundle install
Now we can start the local server (watch autoenabled) with:
$ jekyll serve
For crossposting to Medium, set variables as described here and build:
$ MEDIUM_INTEGRATION_TOKEN=... MEDIUM_USER_ID=... jekyll build